The proposed research will be a systematic biochemical investigation of the mechanism of E. coli RNA polymerase. The rate-determining step in RNA chain initiation will be studied using kinetic and spectrofluorometric techniques. The detailed role of sigma subunit will also be investigated. The mechanism of action of certain antibiotic inhibitors of RNA synthesis such as rifamycin and actinomycin will be studied. The mechanistic work is seen as a foundation on which studies of the control of transcription can be pursued. We want to know how ribosomal RNA synthesis is controlled in E. coli and how the positive control factor from gene N of bacteriophage lambda functions. We also want to describe the biochemical basis of promoter mutations.